1. D. Johnson, B → $$ D\overline{D}h $$ decays: a new (virtual) laboratory for exotic particle searches at LHCb, LHC seminar, CERN, Geneva, Switzerland, 11 August 2020.
2. LHCb collaboration, Amplitude analysis of the B+ → D+D−K+ decay, arXiv:2009.00026 [INSPIRE].
3. M. Karliner and J.L. Rosner, First exotic hadron with open heavy flavor: $$ cs\overline{u}\overline{d} $$ tetraquark, Phys. Rev. D 102 (2020) 094016 [arXiv:2008.05993] [INSPIRE].
4. M.-W. Hu, X.-Y. Lao, P. Ling and Q. Wang, The X0(2900) and its heavy quark spin partners in molecular picture, arXiv:2008.06894 [INSPIRE].
5. X.-G. He, W. Wang and R. Zhu, Open-charm tetraquark Xc and open-bottom tetraquark Xb, Eur. Phys. J. C 80 (2020) 1026 [arXiv:2008.07145] [INSPIRE].